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Unless you’ve been living under a rock—in which case: kudos—you’ve likely noticed that bicycle tyres have gotten wider. and in addition to aerodynamic refinements, tyre clearance is one of the primary features highlighted in new bike releases. In fact, many modern road racing frames now have clearance for up to 35 mm tyres—and sometimes more.
Despite this happening for some time now, appropriately wider wheels have not been forthcoming. Over the last few months, that has changed: DT Swiss, Zipp, and now British wheel company Parcours are finally introducing rims that match wider tyres.
The concept is straightforward enough: for optimal aerodynamics, rims should be slightly wider than tyres; however, for tyres over 40 millimetres wide, this creates problems. Extremely wide rims are heavier and can run afoul of ETRTO guidelines for tyre compatibility with internal widths that are unsafe with narrower tyres. Also, the combination of larger tyres with deeper rims can perform adversely at significant yaw angles, i.e., crosswinds.
As such, developing wider rim profiles has taken time. UK-based Parcours has invested heavily in wind tunnel testing to develop products and overcome these complex design parameters. In the course of the company’s research, it found that tyre tread has a surprisingly large impact on aerodynamic performance. To address this, Parcours decided to design the FKT wheels around a specific gravel race tyre, the Panaracer GravelKing X1, and optimised the rim profile for its individual aerodynamic performance. This sort of design collaboration, in which the larger system is examined as a whole instead of focusing on individual parts, is increasingly common in the industry.
Design and features
(Image credit: Tyler Boucher)
The Parcours FKT wheelset utilises a truncated foil rim shape that measures 47 millimetres deep and 40 millimetres wide. The hybrid Kamm profile is designed to work both as a leading and trailing edge when cutting through the air. Internal width measures 27 mm, which makes these wheels ETRTO compliant with tyres as small as 35 mm. The design is optimised around 40 mm tyres, and compatible with tyres up to 55 mm. Rims are hookless and Parcours uses a more flexible resin at the rim edge for impact resistance. Hubs are built with a 6-pawl freehub running on a 44T ratchet drive mechanism. FKT wheels are available with either steel or ceramic bearings or built to a Classified Powershift-ready hub. Weight is a competitive (stated) 1500 grams.
Specs
The ride
(Image credit: Tyler Boucher)
Parcours sent along a test set of FKTs paired with 40 mm Panaracer GravelKing X1 tyres—the tyres they were designed for. I didn’t have any issues during setup with the supplied valves and other accoutrements and rode the GravelKings long enough to get acquainted with them before switching to more familiar tyres for testing. I opted for Rene Herse Steilacoom knobbies, listed at 38 mm, which measure 39.5 on these 27 mm internal rims.
Initial impressions on pavement were positive. According to Parcours’s testing, the FKT wheels are good for a roughly 6 watt increase over a standard gravel rim at race speeds. It’s enough to create a slight feeling of tailwind, especially at higher velocities. It was hard to tell a difference at lower speeds, but fast wheels help make it easier to keep pushing when you’re riding hard. Most of my testing was on calm days, so I didn’t get to feel the FKT wheels in significant crosswinds, but crossing over the long bridges across Lake Washington that are part of my usual training routes is always blustery and I never once was made uncomfortable by the wheel’s performance. My recent experience on these wheels and other wide rims seems to demonstrate that width helps with stability in crosswinds.
(Image credit: Tyler Boucher)
I also tested the FKTs in a few cyclocross races to see how they would hold up, as I didn’t have any gravel racing on the calendar during the testing period. There are some obvious similarities between gravel and ‘cross, but some notable differences as well. Straight line speed is much less critical in ‘cross and the emphasis is really on line choice and speed through corners. In my first race I managed to burp my front tyre on the first lap, causing me to crash. To be fair, I did the exact same thing, on the exact same corner last year while riding a different wheelset.
My next race went better. I had zero issues with wheels or tyres, and appreciated the very slight aerodynamic assistance during the few fleeting moments of high speed. More importantly, though, I was able to test the rim’s impact resistance and put them through some hard side loading and torsional testing.
I’ll be curious to see how they hold up over the course of the entire season, but so far, so good. The wheels have not hindered my racing (I’m fully capable of that myself) and they’ve remained true even after a few wipeouts. As these are $1600 wheels, comparing them against higher end options isn’t a fair fight, but it seems that the hubs are perhaps where Parcours was able to keep the price down. The finish isn’t as nice as it could be, and the provided lock rings feel flimsy. I was able to get the hubs to give some feedback under hard pedalling—as if the pawls were sticky, even while new. Also, the freehub is noisy, if you like that sort of thing.
Value and Conclusion
(Image credit: Tyler Boucher)
Smaller companies have to do more to differentiate themselves from the competition. Parcours has decided to go all in on wind-tunnel testing, at significant time and cost, and are putting out products that perform based on (what seems to be) sound science. The FKT wheels bring an impressive aerodynamic performance for the price. Even though tyres have been getting wider for several years, it’s only been the last few months that wider wheels are available to consumers. Parcours seems to be on the forefront with the launch of the FKT.
During the course of my testing, I was impressed by how they felt on the road. At regular cruising speeds the aerodynamic boost is minimal, but at high speeds you can feel the wheels wanting to fly. For the price, these are a very impressive bit of kit. The hubs aren’t amazing, but they get the job done.
Also notable is Parcours’ lifetime warranty, as well as a very reasonable crash replacement policy.
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